Barrel-reamer



iUNITED STATES PATENT OFFICE.

FRANK 0. HOAGLANID, OF HART'FORD, CONNECTICUT, ASSIGNOR TO PRATT &WHITNEY COMPANY, OF NEW YORK, N. Y., A CORFORATION OF NEW J ERSEY. I

BAnREL-BEAMEB.

Application filed. June 8, 1917.

To all Iwhom z't may concern Be it known that I, FRANK O. HOAGLAND, acitizen ofthe United States, residing at Hartford, in the county ofHartford and State of Connecticut, have invented certain new and usefulImprovements in Barrel- Reamers, of which the following is aspecification.

The invention relates particularly to reamers adapted to be used in longor deep holes such as those in rifle barrels. Heretofore considerabledifliculty has been encountered in doing work of this class. There hasbeen a marked tendency for the reamers t`o grip or adhere to the sidesof the bore and become broken, and'even when this did not happen therewas difliculty in removing the chips from the several cutting edgeswhich were provided. Furthermore, only a very small amount of 'metalcould be removed at a single Operation, and when it was necessary toremove larger amounts of metal several successive operations werenecessary.

The principal object of the invention 1s to provide an improved reamersuited for Operation in long or deep'holes and adapted to remove arelatively large amount of metal without encountering dfiiculties suchas those above referred to. v

In the accompanying drawing I have shown several embodiments of theinvention in order that the scope and application thereof may be clearlyperceived. It will be understood, however, that the drawing is intendedto be merely illustrative and is not intended to define or limit thescope of the invention, the accompanying claims being relied upon forthat purpose.

Figure 1 is a side view of a reamerV embodyingthe invention.

Fig. 2 is a side view similar to Fig. 1 but showing a differentembodiment of the invention. p

Fig. 3 is another view similar to Fig. 1 but showing a still differentembodiment of the invention. e

Fig. 4: is an end view, on a greatly enlarged scale, of the reamer shownin Fig. 1,

the view being taken from the, left.

Fig. 5 is a transverse sectional view on the same scale as Fig. 4showing an embodiment of the invention different from that shown in Fig.4. This view can be understood as being taken along the line b-b of Fig.1.

Specification of Letters Patent.

Patented Dec. 2, 1919.

Serial No. 173,439. i

The drawing shows reamers adapted for I reaming relatively small holes,but it is to be understood that the invention is not so limited and thatwith suitable modifications it is possible to construct larger reamersembodying the invention.

Referring first to Figs. 1 and 4: of theV drawing, A represents the maincutting section of the reamer. This section is tapered, increasing indiameter from the plane a-a: to the plane 6-22. The taper is greatlyexaggerated in the drawing in order that it may clearly appear. Inpractice,vhowever, in a reamer such as is used for reaming riflebarrels, the taper may be between three and four one-hundredths of aninch. Adjacent the section A is a section B which prefwhich the reameris provided.

In reamers as heretofore constructed, a great deal of difficulty hasbeen encountered because of the tendency of the outer walls of thereamer to grip or adhere to the surface of the bore. I avoid all suchdifliculties by relieving the outer wall of the reamer in such a waythat it contacts with the surface of the bore only at the cutting edge'2and at a point 3d which is nearly opposite the cutting edge. Preferably,as shown in Fig. 4, the point 3 is located a little less than 180 fromthe cutting edge 2. The location of the point 3 a little less than 180from the cutting edge 2 makes it possible for the reamer rto be firmlysupported and guided by the wall of the bore. If the point of tangency 3were exactly opposite the cutting edge there might be a tendency for awedging action which would produce chattering and uneven cutting. .Thewall of the reamer from the cutting edge 2 to the point 3 conforms tosmooth curves which touch the wall of the bore at 2 and 3. The curvesbegin to deviate from the respective cutting circles immediately behindthe cutting edge. By the cutting circles I mean the circles CJi whichare followed by the several points along the cutting edge, these circles'conforming, or approximately conforming, to the Outline of the bore.From the point 3 to the point 4 at the side of the notch opposite to thecut-ting edge the curves are continued and lie within the outline of thebore. It will be understood that the amount of relief is considerablyexaggerated in Fig. et in order that it may be clearly seen. Inpractice, the amount of relief will ordinarily be but a few thousandthsof an inch.

As concerns the broader features of my invention, I do not limit myselfto any particular form of curve for the outer wall of the reamer, but Iprefer to form the outer wall, at least between the points 2 and 3, inthe form of spirals which are constructed about a center 5 eccentric ofthe center of the bore, designated by 6. The center 5 is located on thediameter which passes through the point 2 and is on the opposite side ofthe center 6. As illustrated in Fig. 4, the center 5 is so positionedthat the spirals constructed about it have points of tangency with thecutting circles and with the Outline of the bore at 3. As shown in thisfigure, the spirals are continued beyond the point 3 and terminate at4:.

It will be seen that when relative turning is effected in the directionof the arrow in Fig. i, the cutting edge 2 will be forced along thesurface of the bore and the reamer will be held in central relationshipto the bore by reason of the engagement between the wall of the reamerand the surface of the bore at 3. At all other points the wall of thereamer and the surface of the bore are out of engagement, thus making itimpossible for the reamer to bind or adhere. Preferably, as shown inFig. 1, the cutting edge 2 is notched at 2a so as to break up the chipswhich are removed.

Anyone of several constructions may be provided for controlling anddriving the sections A and B of the reanier. As shown in Fig. l, thereamer is provided with a pilot or plug section C which has a diameterslightly greater than the smallest diameter of the section A. This pilotsection C is very slightly smaller than the original diameter of thehole to be reained and assists in guiding the reanier and in holding itcentral. The pilot section C is connected with the section A through anintermediate neck section D of reduced diameter. Connected with thesection C is a driving stem E by means of which the reamer is operated.For supplying oil to the groove 1 and to the cutting edge 2 there isprovided a central oil hole 7 which extends through the stem E and thepilot C and intersects the groove 1 at 84. As illustrated, the groove lis closed atl one end adjacent the point of communi- Qatinn Wthrthe 01.1hele, 7. In. 7practice the stem E is connected with a suitable tube orhollow rod, the connection usually being made by 'brazing The centralaperture of the tube. registers with the .hole 7 and at the other end ofthe tube suitable means are provided for supplying oil under highpressure.

Relative rotative movement is elfected between the reamer and the deviceto be reamed, and in the case of a rifle barrel the roaming is usuallyeffected by means of a machine which holds the barrel against rotativemovement and which rotates the reamer relatively thereto. In Operation,therefore, it may be considered that the reamer is rotated. At the sametime relative feeding movement is effected to oarry the reamer deeperinto the bore. Usually the reamer is held against longitudinal movementand the barrel is fed. In the case of the construction shown in Fig. 1,the movement of the barrel is toward the right indicated, and the boreis enlarged to a diameter equal to that of the reamer att-J).

During Operation, oil under high pressure is supplied through the hole 7and enters the groove l through the Opening at 8. The plug section Cprevents the oil from fiowing back toward the left.

The oil which enter-s the groove l serves not only to lubricate thecutting edge and to provide a film of oil between the wall of the rcamerand the surface of the bore, but also serves to carry away the chipswhich. are removed by the cutting edge 2. This latter function of theoil is very important as it prcvents the reamer from becoming clogged.I/Vith earlier constructions having a plurality of cutting edges and aplurality of grooves, much diflicu ty was encountered because of thetendency for one or more of the grooves to become clogged, the oilflowing out through the remaining grooves. As soon as any one groovebecame even partially clogged the flow of oil through that groove wasimmediately lessened7 thus automatically increasing the clogging. rI`heresult was that in earlier reamers all but one or two of the grooveswere clogged very quickly after the cutting Operation started. lvith myimproved reamer the oil must necessarily flow through the one groovewhich is provided, and any possible clogging is entirely prevented.

The form of the reamer shown in Fig. 1 is known as a. pullli` reamer,but my invention is equally Well adapted to be embodied in a pushreamer. Such a reamer is shown in Fig. 2. This reamer comprises sectionsA' and B' which are similar respectively to the sections A and B of thereamer shown in Fig. l. A groove lI extends longitudinally of thesesections but terminates a short distance from the left-hand end of thesection B'. A cutting edge 2' is pro- :viden at one. side-of the groove1' and thev sections A' and B' are relieved in the way alreadydescribed. I prefer not to provide a pilot section such as is shown inFig. 1. This is not needed to direct the oil and I find that without itthe reamer will in many cases cut more accurately. A stem E' isconnected with the left-hand end of the section B' and is provided withan oil hole 7' which communicates with the groove 1' This reameroperates in the same way as the reamer shown in F ig. 1 except that therelative feeding movement is in the opposite direction, the rifie barrelbeing fed toward the left as indicated. The chips are forced out of thegroove l' in advance of the reamer instead of behind it.

In 3 I have shown a reamer adapted for hand use or for use in a turretlathe. This comprises sections A' and B' similar respectively to thesections A and B of the reamer shown in Fig. 2. This reamer is providedwith a longitudinal groove 1' similar to the groove l, and at 2" thereis provided a cutting edge similar to the cutting edge 2'. The sectionsA and B" are relieved in the way already described. Connected with theleft-hand end of the section B" is a shank E by means of which thereamer may be rotated oiheld against rotation as required. It Will beobvious that means may be added for snpplying oil if needed.

Under some circumstances it may be desirable to provide a form of reliefslightly different from that already described and shown in Fig. This isillustrated in Fig. 5, which inay be considered to be a cross sectiontaken along the line b-b of Fig. 1. The form of relief differs from thatshown in Fig. f-l in that the wall of the reamer from the point 3 to thepoint 4 conforms to circular arcs constructed about the center 5. Itwill be noted that because of the eccentricity of the center 5 thecircular arcs between 3 and et lie within the outline of the bore. Thisconstruction is preferable in some cases as it provides a smallerclearance between the wall of the reamer near the point 4; and theadjacent part of'the surface of the bore. Itwill be understood thatbetween the points 2 and 3 there will be a film of oil extending fromthe point 2 to the point 3, and that there Will be a similar film of oilextending from the point 3 to the point 4:. In some cases, when theconstruction shown in Fig. -l is used, the Opening between the point 4and the wall of the bore will be too great to be filled by an oil film.In such cases I prefer to provide the construction shown in Fig. 5 inorder to reduce the width of this Opening.

What I claim is:

1. A reamer having a single cutting` edge .and a relieved outer wallextending backward in smooth curves from the cutting edge to points oftangency to the cutting circles nearly opposite the cutting edge.

2. A reamer having a single cutting edge and a relieved outer wallextending backward in smooth curves from the cutting edge to points oftangency to the cutting circles a little less than 180 from the cuttingedge.

3. A reamer having a single cutting edge and a smoothly curved outerwall which touches the cutting circles at the cutting edge and which istangent to the said circles at points nearly opposite the cutting edgeand which is elsewhere relieved.

4. A reamer having a single cutting edge and an outer wall conforming tospirals constructed about a center eccentric of the cutting circles andextending from the cutting edge at least to points nearly oppositethereto, the said outerv wall having points of tangency with the cuttingcircles.

5. A reamer having a single cutting edge and a relieved outer walleXtending back- Ward in spiral curves from the cutting edge to points oftangency to the cutting circles nearly opposite the cutting edge.

6. A reamer having a single cutting edge and an outer wall partlyconforming to spirals constructed about a center eccentric of thecutting circles and partly conforming to circular arcs constructed aboutthe said eccentric center.

7. A reamer comprisi'ng a single piece of metal approximately circularin general transverse sectional Outline and having a sector ofapproximately 90 removed to provide a single cutting edge, the outerwall being relieved to provide points of intersection With the cuttingcircles at the cutting edge and at points of tangency to the cuttingcircles nearly opposite the cutting edge.

8. A reamer approximately circular in general transverse sectionaloutline and having a: longitudinal sectoral groove which provides asingle cuttingedge and a central longitudinal oil hole at one end whichcommunicates with the sectoral groove, the reamer being provided at thelast said end with a plug section which prevents the escape of oil atthat end.

In testimony whereof I hereto aflix my signature.

FRANK O. HOAGLAND.

